BBR Tuning Motorized Bike Jackshaft Kit CHANGE GEARS EASILY: The BBR Tuning Motorized Bike Jackshaft Kit enables you to use your existing gears, derailer and shifter on your handlebar to shift the gears your engine is powering. This allows you to have a wide range of gear ratios for your engine from low end which makes taking off easy and top end gears that help when cruising at high speeds so that your engine is not running at a high rpm for extended amounts of time. NO LOSS OF PEDALS: Even though your engine is now powering your bicycle chain and sprocket you can still ride your bike just like normal. Your crank's sprocket features a 1 way bearing so that it does not lose function for pedaling like a regular bike. EXPERIENCE BUILDERS RECOMMENDED: This is difficult to install and we highly recommend experience builders install this kit. Since all bikes are different this kit does not include instructions. *NOTE: This kit will allow your bicycle to reach dangerously high speeds, make sure your bike is best suited for high speed use. UNIVERSAL FITMENT: This kit is designed to work with most bicycle engine kits installed on bicycle with multiple speeds and a rear derailer. Without a rear derailer you will not be able to shift gear. PACKAGE INCLUDES: 1x BBR Tuning Gas Powered Motorized Bicycle Jack Shaft Complete Installation Kit